Fix Environment Cleanup (#219)

* fix(Environment): add null checks for scene properties before resetting values

- Added null checks for app.scene.skybox and app.scene.envAtlas to prevent potential errors during cleanup.
- Wrapped scene reset logic in a conditional to ensure app.scene exists before attempting to modify its properties.

* fix(Environment): improve cleanup process

- Added a changeset to address an issue with Environment cleanup in the @playcanvas/react package.
- Ensures proper handling during environment reset to prevent potential errors.

* Update packages/lib/src/components/Environment.tsx

Co-authored-by: Copilot <[email protected]>

* Update packages/lib/src/components/Environment.tsx

Co-authored-by: Copilot <[email protected]>

---------

Co-authored-by: Copilot <[email protected]>

Author: marklundin

.changeset/eleven-crabs-behave.md

@@ -0,0 +1,5 @@
+---
+"@playcanvas/react": patch
+---
+
+Fixes issue with Environment cleanup

packages/lib/src/components/Environment.tsx

@@ -78,7 +78,9 @@ function Environment(props: EnvironmentProps) {
         app.scene.skybox = skybox;  
 
         return () => {
-            app.scene.skybox = null;
+            if (app?.scene) {
+                app.scene.skybox = null;
+            }
         };
     }, [appHasEnvironment.current, safeSceneProps.skybox?.id]);
 
@@ -93,7 +95,9 @@ function Environment(props: EnvironmentProps) {
         app.scene.envAtlas = safeSceneProps?.envAtlas?.resource as Texture ?? null;
 
         return () => {
-            app.scene.envAtlas = null;
+            if (app?.scene) {
+                app.scene.envAtlas = null;
+            }
         };
     }, [appHasEnvironment.current, safeSceneProps.envAtlas?.id]);
 
@@ -140,17 +144,19 @@ function Environment(props: EnvironmentProps) {
              * TODO: Find a better way to reset the scene and sky.
              */
 
-            app.scene.exposure = 1;
-            app.scene.skyboxRotation = new Quat().setFromEulerAngles(0, 0, 0);
-            app.scene.sky.node.setLocalScale(1, 1, 1);
-            app.scene.sky.node.setLocalPosition(0, 0, 0);
-            app.scene.sky.center.set(0, 0.05, 0);   
-            app.scene.sky.type = SKYTYPE_INFINITE;
-            app.scene.sky.depthWrite = false;
-            app.scene.skyboxMip = 0;
-            app.scene.skyboxLuminance = 0;
-            app.scene.skyboxIntensity = 1;
-            app.scene.skyboxHighlightMultiplier = 1;
+            if (app.scene) {
+                app.scene.exposure = 1;
+                app.scene.skyboxRotation = new Quat().setFromEulerAngles(0, 0, 0);
+                app.scene.sky.node.setLocalScale(1, 1, 1);
+                app.scene.sky.node.setLocalPosition(0, 0, 0);
+                app.scene.sky.center.set(0, 0.05, 0);   
+                app.scene.sky.type = SKYTYPE_INFINITE;
+                app.scene.sky.depthWrite = false;
+                app.scene.skyboxMip = 0;
+                app.scene.skyboxLuminance = 0;
+                app.scene.skyboxIntensity = 1;
+                app.scene.skyboxHighlightMultiplier = 1;
+            }
         };
 
     }, [